It could be a ringer, if I were you I would get a RAC or AA inspection before any other further contact with DVLA as once their involved it is truly out your hands and you could be out of pocket. Whereas if you still have the car then you may have a chance of the garage offering you some money back as it's amazing what the mention of police and trading standards can do!
Just googled vehicle ring and this is what it came up with.
Vehicle ringing
A ‘Ringer’ is a stolen vehicle that has had its identification numbers replaced by a set from another written-off model and is supplied with bogus documentation.
Ringers have their VIN (Vehicle Identification Number) replaced, so look for evidence of tampering around where the number is recorded. You can find the number on a small plate riveted under the bonnet and stamped on the vehicle’s chassis, under the carpet beside the front seat. In addition, the VIN will sometimes appear in the door pillar or at the base of the windscreen.
If you buy a ringer, it doesn’t legally belong to you, and will be returned to the owner or insurance company if and when it is traced back to you.
Follow these steps to avoid that happening:
Ensure the V5C registration document (logbook) is genuine, with a DVLA watermark running through it
Check for tampering around the VIN numbers
Make sure there is a satisfactory amount of paperwork
https://www.theguardian.com/lifeandstyle/2005/dec/14/8
Was the garage that you bought the car from the one that did it's last MOT?